--- os.ml.orig	2013-10-24 12:41:54.000000000 +0200
+++ os.ml	2013-10-24 13:27:27.000000000 +0200
@@ -322,18 +322,32 @@
     let s =
       if i=0 then suffix
       else Printf.sprintf "..%03d.%s" i suffix in
+
+    (* Do not use longer temp-file names than the file system permits.
+     * eCryptfs has the lowest file name length limit I know of: 143 bytes.
+     *)
+
+
+
     let tempPath =
       match Path.deconstructRev path with
         None ->
           assert false
       | Some (name, parentPath) ->
           let name = Name.toString name in
-          let len = String.length name in
-          let maxlen = 64 in
+          let nameLen = String.length name in
+          let maxFileNameLength = 143 in (* eCryptfs limit *)
+          let prefixLen = String.length prefix in
+          let suffixLen = String.length s in
+          let maxLen = maxFileNameLength - prefixLen - suffixLen in
+
           let name =
-            if len <= maxlen then name else
-            (truncate_filename name maxlen ^
-             Digest.to_hex (Digest.string name))
+            if nameLen <= maxLen then name else
+              let nameDigest = Digest.to_hex (Digest.string name) in
+              let nameDigestLen = String.length nameDigest in
+              let maxLen = maxLen - nameDigestLen in
+              assert(maxLen>0);
+              (truncate_filename name maxLen ^ nameDigest)
           in
           Path.child parentPath (Name.fromString (prefix ^ name ^ s))
     in